Fix debug C/C++ with lldb-mi in VSCode on MacOS stdin issue

fix-lldb-mi-macos-vscode-stdin.md

Problem: when debugging the programs with lldb-mi on MacOS with VSCode-cpptools, the buildin terminal of VSCode not used as the stdin&out interface.

Fix:

1. enable external terminal
2. use stdin file while debugging and pass the file path using debugger setup command.

Notes:

1. the "args": ["<", "${fileDirname}/data/${fileBasenameNoExtension}"]will not work (at least for now) on MacOS because it treats the redirect operator as program argument.
2. the 1. does work with gdb-mi (on Linux) though.
3. if not want to use stdin, just enable the external terminal and in put the data manually during debugging at external terminal window.

Ref: microsoft/vscode-cpptools#1219 (comment)

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(lldb) Launch",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}/${fileBasenameNoExtension}",
            // "args": ["<", "${fileDirname}/data/${fileBasenameNoExtension}"], // not work, will take as argv to the programe
            "args": [],
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            // "externalConsole": true,
            "MIMode": "lldb",
            "setupCommands": [ // nether setup command will read data from a file on disk as stdin to the target program
                {
                    "text": "settings set target.input-path ${fileDirname}/data/${fileBasenameNoExtension}"
                }
            ]
        }

    ]
}